The purpose of the study is to characterize the pharmacokinetic (PK) profile of cetrelimab administered subcutaneous (SC) and optionally intravenous (IV) in chronic hepatitis B (CHB) participants.

Hepatitis B virus (HBV) is a small deoxyribonucleic acid (DNA) virus that infects the liver and can cause either acute (less than 6 months) or chronic (more than 6 months) infection. Persistence of HBV infection requires antigen-specific immune tolerance that prevents clearance of infected cells. Cetrelimab (JNJ-63723283) is a fully human immunoglobulin (Ig) G4 kappa monoclonal antibody (mAb) that binds to programmed cell death receptor-1 (PD-1) with high affinity and specificity. PD-(L)1 inhibitors could possibly reverse the immune dysfunction from HBV. The study will be conducted in 3 phases: a screening phase (6 weeks), a single dose intervention phase (1 day), and a 24-week follow-up phase. The duration of individual participation will be up to 30 weeks. Key safety assessments include monitoring of Adverse Events (AEs), physical examination, vital signs, Electrocardiogram (ECGs), Injection site reaction (ISRs), Infusion-related reaction (IRRs), and clinical laboratory tests.

Inclusion Criteria:

• Must have chronic hepatitis B virus (HBV) infection documented
• Participants should be virologically suppressed, Hepatitis Be antigen (HBeAg) status (positive or negative) be on stable Nucleotide analog (NA) treatment for at least 6 months
• Must have: a) A liver biopsy result classified as Metavir F0-F2 within 2 years prior to screening; b) If a liver biopsy result is not available: Fibroscan liver stiffness measurement less than or equal to (<=) to 9.0 kilopascals (kPa) within 6 months prior to screening or at the time of screening
• Must be medically stable
• Must have a body mass index (weight in kilogram [kg] divided by the square of height in meters) between 18.0 and 30.0 kilograms per meter square (kg/m^2), extremes included

Exclusion Criteria

• History or evidence of clinical signs or symptoms of hepatic decompensation, including but not limited to: portal hypertension, ascites, hepatic encephalopathy, esophageal varices
• Participants with evidence of liver disease of non-HBV etiology.
• Participants with history or signs of cirrhosis or portal hypertension (nodules, no smooth liver contour, no normal portal vein, spleen size greater than or equal to [>=] 12 centimeters) or signs of hepatocellular carcinoma (HCC) on an abdominal ultrasound performed within 6 months prior to screening or at the time of screening
• History of malignancy within 5 years before screening (exceptions are squamous and basal cell carcinomas of the skin and carcinoma in situ of the cervix, or malignancy, which is considered cured with minimal risk of recurrence)

The data sharing policy of the Janssen Pharmaceutical Companies of Johnson & Johnson is available at www.janssen.com/clinical-trials/transparency. As noted on this site, requests for access to the study data can be submitted through Yale Open Data Access (YODA) Project site at yoda.yale.edu